piatra vanata= CuSO4 .5 H20
Mpiatra vanata= Msulfat cupros +5*Mapa=160+90=250
c=md*100/ms => md=c*ms/100=17*245/100=41.65 substanta anhidra
250g piatra vanata-------160g CuSO4-----------90g APA
X--------------------------------41.65
X=250*41.65/160=65.078 grame piatra vanata